package org.apache.helix.webapp.resources;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  import java.io.IOException;
  import java.util.List;
  
  import org.apache.helix.HelixException;
  import org.apache.helix.ZNRecord;
  import org.apache.helix.manager.zk.ZkClient;
  import org.apache.helix.tools.ClusterSetup;
  import org.apache.helix.webapp.RestAdminApplication;
  import org.apache.log4j.Logger;
  import org.codehaus.jackson.JsonGenerationException;
  import org.codehaus.jackson.map.JsonMappingException;
  import org.restlet.Context;
  import org.restlet.data.MediaType;
  import org.restlet.data.Request;
  import org.restlet.data.Response;
  import org.restlet.data.Status;
  import org.restlet.resource.Representation;
  import org.restlet.resource.Resource;
  import org.restlet.resource.StringRepresentation;
  import org.restlet.resource.Variant;
  
  
  public class ClustersResource extends Resource
  {
    private final static Logger LOG = Logger.getLogger(ClustersResource.class);
  
    public ClustersResource(Context context, Request request, Response response)
    {
      super(context, request, response);
      getVariants().add(new Variant(MediaType.TEXT_PLAIN));
      getVariants().add(new Variant(MediaType.APPLICATION_JSON));
      // handle(request,response);
    }
  
    @Override
    public boolean allowPost()
    {
      return true;
    }
  
    @Override
    public boolean allowPut()
    {
      return false;
    }
  
    @Override
    public boolean allowDelete()
    {
      return true;
    }
  
    @Override
    public Representation represent(Variant variant)
    {
      StringRepresentation presentation = null;
      try
      {
        presentation = getClustersRepresentation();
      }
      catch (Exception e)
      {
        LOG.error("", e);
        String error = ClusterRepresentationUtil.getErrorAsJsonStringFromException(e);
        presentation = new StringRepresentation(error, MediaType.APPLICATION_JSON);
  
        e.printStackTrace();
      }
      return presentation;
    }
  
    StringRepresentation getClustersRepresentation() throws JsonGenerationException,
        JsonMappingException,
        IOException
    {
      ZkClient zkClient =
          (ZkClient) getContext().getAttributes().get(RestAdminApplication.ZKCLIENT);
      ClusterSetup setupTool = new ClusterSetup(zkClient);
     List<String> clusters = setupTool.getClusterManagementTool().getClusters();
 
     ZNRecord clustersRecord = new ZNRecord("Clusters Summary");
     clustersRecord.setListField("clusters", clusters);
     StringRepresentation representation =
         new StringRepresentation(ClusterRepresentationUtil.ZNRecordToJson(clustersRecord),
                                  MediaType.APPLICATION_JSON);
 
     return representation;
   }
 
   @Override
   public void acceptRepresentation(Representation entity)
   {
     try
     {
       JsonParameters jsonParameters = new JsonParameters(entity);
       String command = jsonParameters.getCommand();
 
       if (command == null)
       {
         throw new HelixException("Could NOT find 'command' in parameterMap: " + jsonParameters._parameterMap);
       }
       else if (command.equalsIgnoreCase(ClusterSetup.addCluster))
       {
         jsonParameters.verifyCommand(ClusterSetup.addCluster);
 
         ZkClient zkClient =
             (ZkClient) getContext().getAttributes().get(RestAdminApplication.ZKCLIENT);
         ClusterSetup setupTool = new ClusterSetup(zkClient);
         setupTool.addCluster(jsonParameters.getParameter(JsonParameters.CLUSTER_NAME),
                              false);
       }
       else
       {
         throw new HelixException("Unsupported command: " + command
             + ". Should be one of [" + ClusterSetup.addCluster + "]");
       }
 
       getResponse().setEntity(getClustersRepresentation());
       getResponse().setStatus(Status.SUCCESS_OK);
     }
     catch (Exception e)
     {
       getResponse().setEntity(ClusterRepresentationUtil.getErrorAsJsonStringFromException(e),
                               MediaType.APPLICATION_JSON);
       getResponse().setStatus(Status.SUCCESS_OK);
       LOG.error("Error in posting " + entity, e);
     }
   }
 
   @Override
   public void removeRepresentations()
   {
 
   }
 }